Procedure for selection of the SPD system according to the probability of damage

In the present paper practical recommendations and procedures are proposed for selection of an SPD system with aim to protect, with a given probability, electronic and electrical apparatus within a structure against overvoltages coming from different sources of damage as defined by IEC 62305 [1]. The investigations are based on several computer simulations, by means of commercial transient software EMTP-RV, at the typical basic arrangement consisting of an apparatus within a structure influenced by direct flashes to the structure (source of damage S1), flashes to ground nearby the structure (source of damage S2), flashes to power and communication lines connected to the structure due to flashes to and near the lines (sources of damage S3 and S4). This work is executed in focus on the frame of discussion on recommendation of IEC/EN 62305 [1] for the selection of coordinated SPD system able to reduce the failure of the apparatus with a given probability.